in the total ordering such that the other predecessors of Xi are conditionally independent of Xi givenparents(Xi). That is, parents(Xi) ⊆{X1,...,Xi-1} such that
P(Xi|Xi-1...X1) = P(Xi|parents(Xi)).
If more than one minimal set exists, any minimal set can be chosen to be the parents. There can be more than one minimal set only when some of the predecessors are deterministic functions of others.
We can put the chain rule and the definition of parents together, giving